Adjustable electromagnetic relay

ABSTRACT

AN ADJUSTABLE ELECTROMAGNETIC RELAY. A MOVABLE ARMATURE IS HELD, IN ITS INOPERATIVE POSITION, IN CONTACT WITH TWO MAGNETIC POLES OF A YOKE BY MEANS OF A POLARIZING FLUX PRODUCED THROUGH THE ARMATURE BY A PERMANENT MAGNET. AN OPPOSING ACTION IS CAUSED BY A SPRING WHICH EXERTS ON THE MOVABLE ARMATURE AN OPPOSING FORCE TENDING TO MOVE IT AWAY FROM ITS HELD POSITION. WHEN A FLUX IS PRODUCED BY A CONTROL WINDING THROUGH THE ARMATURE IN A DIRECTION OPPOSITE TO THAT OF THE POLARIZING FLUX, THE ARMATURE BECOMES UNLOCKED, CEASING TO RESTRAIN THE OPPOSING FORCE AND RELEASING THE MECHANICAL ENERGY OF THE SPRING.

Jan. 26, 1971 c. QUICHAUD I? ADJUSTABLE ELECTROMAGNETIC RELAY 3 Sheets Sheet l Filed Sept. 12, 196.8

VINVENTOR CLAUDE QUICHAUD Jan. 26, 1971 A :c." QUICHAIUD 3,559,129

ADJUSTABLE ELECTROMAGNETIC RELAY I FiledSept. 1968 s Sheds-Sheet 2 FIG .3

INVENTOR CLAUDE QUICHAUD Slbf l- ,R M M BY 4 w' 'x ATTORNEYS Jan. 26, 1971 Y C. QUIQCHAUD 3,559,129

ADJUSTABLE ELECTROMAGNETIC RELAY Filed Sept. 12, 1968 3- Sheets-Sheet 5 INVENTOR CLAUDE QUICHAUD United States Patent Int. Cl. riolr 7/08 US. Cl. 335-229 13 Claims ABSTRACT OF THE DISCLOSURE An adjustable electromagnetic relay. A movable armature is held, in its inoperative position, in contact with two magnetic poles of a yoke by means of a polarizing flux produced through the armature by a permanent magnet. An opposing action is caused by a spring which exerts 0n the movable armature an opposing force tending to move it away from its held position. When a flux is produced by a control winding through the armature in a direction opposite to that of the polarizing flux, the armature becomes unlocked, ceasing to restrain the opposing force and releasing the mechanical energy of the spring.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates to an adjustable electromagnetic relay of high sensitivity.

Description of the prior art Electromagnetic relays are already known which comprise a holding magnet, for example as disclosed in US. Pat. 2,166,091. Such relays generally comprise a permanent holding magnet, cooperating with two magnetic circuits connected in parallel with its terminals. One of these magnetic circuits comprises a movable armature which is attracted by two pole faces. The other magnetic circuit consists of two ferromagnetic parts separated by an air space forming a magnetic shunt. The movable armature is subjected to the opposing action of a spring. Means are provided for adjusting the magnetic shunt, and the force of the spring or its leverage. The reluctance of the armature may be maintained between predetermined limits by adjustment of the air gap present between the armature and the attracting pole faces.

Mass production of low-consumption permanent holding magnets as shown by the prior art is difficult because it is necessary.

(1) To produce, within consistently controlled tolerances, magnetic contacts having very low reluctance be- SUMMARY OF THE INVENTION The present invention has for its object to reduce these dilficulties by adopting constructional features which will produce an electromagnetic relay which requires very low control energy and which is of simple and robust 3,559,129 Patented Jan. 26, 1971 construction, of small overall dimensions, of notably reduced length, and disposed in a fluid-tight casing.

The electromagnetic relay according to the invention is distinguished notably in that the yoke of the relay con-- sists of a magnetic circuit formed of two parallel fiat parts. At one end of the flat parts are two poles and a movable armature. At the other end is an air gap between the two parts of the magnetic circuit, opposite which air gap the permanent magnet is disposed. A nonmagnetic piece is inserted in the intermediate zone to perform the function of a magnetic shunt.

In accordance with another feature of the invention, the two parallel flat parts of the magnetic circuit are separated in their central zone by a non-magnetic insert of small thickness.

In accordance with a further feature of the invention, the position of the permanent magnet opposite the air gap is adjustable so as to modify the flux by which the movable armature is held on the yoke of the relay.

In accordance with another feature of the invention, the movable armature is disposed parallel to the two main parts of the magnetic circuit and applied to two poles consisting of two bent-over parts of the magnetic circuit.

In accordance with another feature of the invention, the relay is disposed in a fluid-tight casing, the fluid-tightness of the control rod being ensured by a diaphragm which surrounds the point from which the said rod extends and which forms a bellows.

In accordance with yet a further feature of the invention, the yoke of the relay comprises essentially two fiat parts of substantially rectangular form, one of which is bent over in L-form to form the two poles to which the movable armature is applied.

In accordance with a further feature of the invention, the yoke of the relay comprises two flat pole pieces assembled by screws and a non-magnetic insert of small thickness engaged between two flat surfaces of the pole pieces to maintain a gap of said small thickness between the two fiat pole pieces and thus to control the reluctance of a high reluctance magnetic shunt path across the nonmagnetic insert.

In accordance with yet a further feature of the invention, the movable armature is mounted on a pivotable support on which the mechanical energy accumulator acts.

In accordance with another feature of the invention, the mechanical energy accumulator or spring is adjustable by means of an adjusting screw.

In accordance with yet a further feature of the invention, the permanent magnet is applied to the yoke by a spring.

In accordance with another feature of the invention, the adjustment of the position of the permanent magnet is effected by means of a counter-pressure spring and an adjusting screw.

In accordance with another feature of the invention, the support of the movable armature, which consists of a single piece, comprises a part bent over at a right angle, which is formed with an aperture in which the movable armature is situated, the latter being located to its support by means of a fixing device such as a clip.

In accordance with yet a further feature of the invention, the support of the movable armature is pivotally mounted on the yoke of the relay in Vs in the said yoke.

In one embodiment of the invention, the relay comprises a yoke consisting of two fiat members (or parts) of substantially rectangular form, which are applied one against the other but separated by a non-magnetic insert. These two parts are coupled to a permanent magnet which is disposed parallel to the two parts and is applied under one of them at the position of the air gap situated between the two parts of the yoke on the side opposite to the poles to which the movable armature is applied. The movable armature is held, in its inoperative position, in contact with the magnetic circuit by the flux created in the circuit by the permanent magnet. A movable support is provided which pivots under the action of a spring and a winding on a part of the magnetic circuit to detach the movable armature from the magnetic circuit when a current is passed therethrough.

Further features of the invention will become apparent in the course of the following description of one form of construction of a relay according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates the principle of a relay according to the invention,

FIG. 2 is an exploded view of the magnetic circuit,

FIG. 3 is an elevational view of a relay in section along its longitudinal axis,

FIG. 4 is a view of the relay from above, the closure cover having been removed, and

FIG. 5 illustrates the mounting of the movable armature in its support.

In the form of construction illustrated in the figures, referring more particularly to FIG. 1, the relay comprises a permanent magnet 1 and a yoke consisting of two flat pole pieces 2 and 3 of substantially rectangular form, which are applied one against the other and separated by a non-magnetic insert 4, a movable armature 5 maintained in its operative or held position on the magnetic circuit by the flux created in the latter by the permanent magnet 1, a winding 6 disposed on the part 2 of the magnetic circuit to detach the movable armature from the magnetic circuit when a current is passed therethrough, the parts 2 and 3 of the magnetic circuit having an air gap 7 between them, the permanent magnet 1 in the form of a short-armed U, being applied under the parts 2 and 3 of the magnetic circuit at the position of the air gap 7. The movable armature 5 is secured to a support 8 which is pivotally mounted on the yoke 3 at the point 9.

As illustrated in FIGS. 2, 3 and 4, the two pole pieces 2 and 3 are of flat rectangular form and are assembled by screws 10 or other similar means and separated by the insert 4 of non-magnetic materials, which is of rectangular form and of small thickness. The pole piece 2 is obtained from a T-shape piece of material. The piece 2 is bent so that in cross section it appears bent in L-form. The coil 6 is wound on the narrow portion formed of the bent arm of the T from a two-part coil. The pole piece 3 is nonlaminated and may advantageously be obtained from a section having the form of a cup-shaped member. This pole piece 3 comprises one or more V-shaped notches 11 serving for pivoting the support 8 of the movable armature 5. These V-shaped notches can be very precisely formed in the section by extrusion or drawing, a single machining operation being necessary for the formation of the said pivots, whereby the trimming operations are simplified. The non-magnetic insert 4 is gripped between two trued surfaces 12 and 13 on the pole pieces 2 and 3, the pole piece 3 being formed with a groove to form the air gap 7 defined between the two pole pieces '2 and 3. A right-angled part 36 of the member 3 permits taking up the thicknesses of the non-magnetic insert 4 and of the member 2, so that the end of the part 36 is on the same plane as the lower face of the member 2. The member 3 also comprises a groove 14 intended to form a pole piece 15 for the movable armature 5.

The magnetic contacts between the movable armature 5 and the pole pieces 2 and 3 are so made that the holding sections are constant and independent of the positioning movement of the armature in its support 8. This condition is satisfied by a cross-shaped overlap of the armature 5 with the pole faces of the yokes 2 and 3, the yoke 3 being for this purpose formed with a groove 14. The armature support 8 (see FIG. 5) pivoting in the V-shaped notches 11 in the yoke 3 comprises a recess 16 serving for the positioning of the armature 5 and transmits the force of a driving spring 17 (see FIG. 3) to the movable armature 5 without any intermediate member. The support 8 is pivotally mounted on the yoke 3 by means of pivoting portions 18 in the V-shaped notches 11 of the yoke 3 and on the other hand by means of a part 19 which is disposed in a recess 20 in the yoke 3. The armature 5 rests in the aperture 16 in the portion 21 bent over at right angle, of the support 8- on an abutment 22 and is guided by two lugs 23, the bosses 24 of the armature 5 being disposed in the recesses 25 in the support 8. Means are provided to connect together the armature 5 and its support 8, for example a clip 26 engaging with the support 8. A screw 27 is provided for the adjustment of the leverage of the force of the driving spring 17 (also called a mechanical energy accumulator) in relation to the pivoting V-shaped notches 11. A counter-pressure spring 28 for the magnet 1, a leaf spring 38 for maintaining the magnet against the magnetic circuit and a screw 29 secured in the casing permits adjusting the holding flux of the movable armature by displacement of the magnet in relation to the groove 7 to short-circuit a part of the magnet 1. The spring 28 may be replaced by a locking screw or other similar means.

The assembly consisting of the pole pieces 2 and 3 is secured in a housing consisting of a casing 30 and its closure cover 31. The movement of the armature 5 is transmitted to the exterior of the relay through a push rod 32.

The fluid-tightness of the transmission is insured by a diaphragm 33 secured, for example, on the closure cover 31 by a collar 43 held by screws 34. The said diaphragm contains a spring 35 hearing, through the diaphragm 33, on a flange on the rod 32, so that a clearance of the order of 0.5 mm., for example, always exists between the movable armature 5 and the end of the rod 32. This feature makes it possible to avoid modification of the operating threshold of the relay by friction of the rod 32 under the action of corrosion in its guide. This operating clearance is adjusted, the rod 32 bearing against the neighboring part of the apparatus to be controlled, for example a protective circuit-breaker, on which the relay is to act mechanically. This clearance may also be insured by the inherent elasticity of the bellows in the case of a metal bellows.

The relay just described operates as follows. In the absence of current in the control winding 6, the magnet 1 distributes a holding flux in the magnetic armature circuit and a flux in the magnetic shunt 4. The armature is maitnained in contact with the pole faces of the yokes 2 and 3. When the direction of the current flowing through the winding is such that the corresponding characteristic flux is subtracted from the flux 4),, and added to the flux the magnetic attracting force of the movable armature 5 decreases and the armature pulled by the spring 17 encounters the push rod 32 and drives it in its movement, thus producing the desired mechanical action on the neighboring part of the apparatus to be controlled.

The application of the invention makes it possible to obtain an electromagnetic relay having the following advantages:

(1) The movable armature and its air gaps in the held position are situated within a fluid-tight housing which protects them from dust and moisture,

(2) The fluid-tightness is so effected that a change of the elastic characteristics of the bellows or a deterioration of the guide of the push rod has no effect on the electrical characteristics of the relay,

(3) The general arrangement adopted, the construction of the pole pieces and the magnetic and mechanical adjusting means permit industrially mastering the manufacture of these relays, while rendering possible the serial manufacture thereof. Their magnetic parameters can be determined without difiiculty. The magnetic circuit formed of two legs of the yoke permits studying all the magnetic characteristics which affect the operation of the relay for a desired control power.

Of course, the invention is in no way limited to the embodiment described and illustrated, which has been referred to only by way of example. More particularly various features may be modified or various means replaced by equivalent means without departing from the scope of the invention. Therefore, the scope of the invention is determined only by the scope of the claims which follow.

What is claimed is:

1. In an electromagnetic relay including a movable armature held, in its unenergized mode, in contact with two magnetic poles of a yoke by a polarizing flux produced through said armature by a permanent magnet, a mechanical energy accumulator exerting on said armature an opposing force tending to move said armature away from its held position, a control winding for releasing the mechanical energy of said accumulator as a result of flux produced through said armature in a direction opposite to that of said polarizing flux, the improvement wherein said yoke cOmprises two flat magnetic circuit members, a thin non-magnetic insert intermediate the ends of said circuit members for maintaining said flat magnetic circuit members parallel to each other and separated from each other, said poles lying on one side of said insert and an air gap lying on the other side of said insert, said poles being closed by said movable armature which is parallel to said fiat magnetic circuit members, and said air gap being closed by said permanent magnet.

2. An electromagnetic relay according to claim 1 further including means for adjusting the position of said permanent magnet in relation to said air gap to modify the amount of flux which acts to hold said armature against said poles.

3. An electromagnetic relay according to claim 2 wherein each of said poles comprises a portion of one magnetic circuit member which is bent over.

4. An electromagnetic relay according to claim 3, wherein the relay is disposed in a fluid-tight casing, said casing including a diaphragm surrounding a control rod at the point from which the said rod extends from said casing, thereby forming a bellows to insure the fluid tightness of the control rod.

5. An electromagnetic relay according to claim 4, wherein the yoke of the relay comprises said two path elements, each including one said fiat portion of substantially rectangular form, and one of said path elements being bent over in L-form to form one of the two poles to which the movable armature is applied.

6. An electromagnetic relay according to claim 5, wherein said yoke of said relay comprises (a) two partially flat path elements assembled by screws and '(b) said non-magnetic insert engaged between two plane surfaces of said path elements and controlling the reluctance of said magnetic shunt path.

7. An electromagnetic relay according to claim 6, wherein said movable armature is mounted on a pivoted support on which said mechanical energy accumulator acts.

8. An electromagnetic relay according to claim 7, wherein said mechanical energy accumulator is adjustable by means of an adjusting screw.

9. An electromagnetic relay according to claim 8, wherein said magnet is applied to said yoke by a spring.

10. An electromagnetic relay according to claim 9, wherein the adjustment of the position of said permanent magnet is effected by means of a counter-pressure spring and an adjusting screw.

11. An electromagnetic relay according to claim 10, characterized in that the support of the movable armature comprises a part of one of said path elements bent over at a right angle, which is formed with an aperture in which the armature is disposed, said armature being locked on its support by means of a securing device. I

12. An electromagnetic relay according to claim 11, wherein the support of said movable armature is pivotally mounted on the yoke of the relay in a V-shaped notch in the said yoke.

13. An electromagnetic relay according to claim 12, wherein said permanent magnet has the form of a shortarmed U.

References Cited UNITED STATES PATENTS 3,432,782 3/ 1969 Ellenberger 335229X 3,360,691 12/1967 Paganelli 33523OX 3,113,251 12/1963 MOser et a1. 335-229 3,053,952 9/1962 Kohler 335179X 2,888,290 5/1959 Pierce 335229X FOREIGN PATENTS 1,390,282 1/1965 France 335-229 BERNARD A. GILHEANY, Primary Examiner D. M. MORGAN, Assistant Examiner 

